Material
Types of Steel Materials
- All component values are expressed as percentage by weight.
- Values preceded by '~' indicate a range.
- Values preceded by '<' indicate a maximum limit.
- The hyphen '-' indicates that the content of the element is not specified or regulated in this context for these particular grades.
| Type of Steel Material | Characteristics |
| Rolled Steels for General Structure | This is the most widely used and cost-effective structural material. Grades like SS400 are abundantly distributed, and variations in shape (sheet, plate, bar, section, etc.) and price make them suitable for a wide range of uses, from building frames to general machinery parts. |
| Cold Drawn Steel Bar (Bright Bar) | Bright refers to the state where hot-rolled steel material is cold-drawn or drawn through dies to smooth the surface. It is often used for general machine parts because the surface smoothness and accurate dimensions obtained by cold drawing ensure a pleasing "beautiful appearance" of the steel. |
| Carbon Steels For Machine Structural Use |
This is one of the most popular structural steels, having a specific gravity of 7.8 and generally used for applications requiring heat treatment. It can be heat treated to obtain high strength, making it suitable for parts like shafts, levers, gears, and fasteners. However, it is not suitable for deep drawing or welding. S45C is often specified for general purpose machinery (Tensile Strength approx. 58 kgf/mm²). |
| Carbon Tool Steels | These are high-purity materials with a C content ranging from 0.6 to 1.5%. They are heat treated by quenching and tempering to achieve high hardness, making them suitable for tools and parts that require superior wear resistance. |
| Alloy Tool Steels | Compared to SK materials (Carbon Tool Steels), these materials have less variation in shape after hardening due to the alloying elements. |
| Chrome Molybdenum Steels |
These are alloy steels containing "Chromium" and "Molybdenum." Adding these elements to machine structural steel (SCM) greatly improves hardenability and creep resistance. Chrome Molybdenum steels are used for critical automotive parts (bolts, nuts, shafts) and other parts exposed to high temperatures, as their strength does not significantly decrease even after long periods at temperatures around 500°C. SCM435 typically has a tensile strength of 70 kgf/mm² or more (Yield strength 95 kgf/mm² or more) and a Brinell hardness of HB270 or less in the as-hot-rolled condition. Hardness reaches HRC50 or more after quenching and tempering. |
| Free-Cutting Steels with Sulfur or Compound Sulfur |
These steels improve machinability by adding elements like S and Pb. SUM materials are specifically designed for processing and have significantly better machinability compared to conventional steels. SUM materials are especially useful when complex shapes or tight tolerances require extensive machining. |
| High Carbon Chromium Bearing Steels | SUJ materials are known as "bearing steels." They are high C-Cr bearing steels and are designated with specific compositions. The high C content (approx. 1.0%) and high Cr content (approx. 1.5%) provide superior hardness and abrasion resistance, which is essential for rolling bearings. This is a very common material widely used in the mass production of mechanical parts that require highly reliable performance at a low cost. |
| Cold Rolled Steel Sheet and Strip | Cold rolled steel is manufactured into flat products by cold working (rolling) hot-rolled steel. SPCC is the most common grade, followed by SPCD and SPCE for deep drawing applications, and SPFC for high strength. SPCC is ideal for applications like covers and cases due to its good dimensional accuracy, smooth and beautiful surface, excellent ductility, and workability. |
| Hot Rolled Steel Sheet and Strip | Hot rolled steel is created by rolling steel ingots at high temperatures, often referred to as black skin due to the scale layer on the surface. Unlike cold rolled steel, it is generally used for parts that do not require a beautiful surface, high accuracy, or deep drawing properties. It is typically low in carbon content and suitable for simple forming and welding. The general maximum thickness is around 6 mm. |